won't you join us? >>> tonight iran's nuclear negotiators arrived back to iran in a crowd of cheering supporters. perhaps because the economic sanctions are about to be lifted. it came after reaching the tentative agreement with the six world powers including the u.s. now, that agreement caused for them to curb their nuclear program for six months. in exchange, some of the economic sanctions imposed on the country will be lifted. tonight, there appears to be doubt on the deal on both sides of the aisle of the senate. ree we're very concerned that it will not be the case. if they save their reaction right now, i mean they're spiking the football in the end zone, saying look, you know, we consolidated our games, we have relieved sanctions. that we're going to have the right to enrich. >> reporter: the agreement of the term indicates that they must be made during the next six months for them to have a more permanent elimination of the capacity to produce a nuclear weapon. and if not the sanctions, they are